<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
  <script src="./vue.js"></script>
</head>
<body>
<div id="root">
  <input type="text" @keydown.13="fn" placeholder="13">
</div>
</body>
<script>
  new Vue({
    el: '#root',
    methods: {
      fn(e){
        console.log(e.keyCode);
      }

    }
  })
</script>
</html>